


Like Rabbits

by MeGaLoTrash



Category: Undertale (Video Game)
Genre: Bunny Costume, Costume Kink, Ecto-Penis (Undertale), Ecto-Tongue (Undertale), Ecto-Vagina (Undertale), Fontcest, M/M, Mirror Sex, Object Insertion, PWP, Papussy, Voyeurism, classic fontcest
Language: English
Status: Completed
Published: 2017-09-17
Updated: 2017-09-17
Packaged: 2018-12-30 20:59:38
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,630
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12117135
Author URL: https://archiveofourown.org/users/MeGaLoTrash/pseuds/MeGaLoTrash
Summary: The Undertale update had Sans thinking about Papyrus in different costumesOne of them was a rabbit costume... and i'm a pervert.Shout out to everyone who didn't discourage me from writing this, you're going down with me ;)





	Like Rabbits

Papyrus ran his fingers through the plush material of the costume that he had been instructed to change into. The costume party wasn’t for another few weeks but Sans had insisted he try it on tonight. Even in his dimly lit bedroom it was very easy to tell what the costume was, he felt a shiver travel up his spine as the realisation hit him.

_How Did Sans Find Out?_

Papyrus had been so careful in hiding his secret fantasies. They had only been dating a few months and he hadn’t wanted to scare his brother off with this particular kink. It was clear Sans had gone put a lot of effort into choosing the outfit, this couldn’t have been a mere coincidence. The dress part of the costume was in a soft pastel pink which felt so soft Papyrus couldn’t wait to feel it on him properly. It also included a matching set of accessories in a darker pink, long gloves, some thigh high socks and a tall pair of bunny ears. The ears were fast become Papyrus’s favourite part, they weren’t small like the pair he had stashed away in secret. They were huge, fluffy, and un-mistakenly bunny like.

_Wowie_

It took Papyrus almost no time to shed the casual clothing he had been wearing that day. He only bothered to half fold them into a pile, he was so excited. He paused before taking his underwear off, he hadn’t seen any in the pile of clothes. Papyrus wondered for a moment whether he should keep what he was in on, but if Sans had wanted him to wear anything he would have included it. After stripping fully Papyrus initially went to put the dress on first, but decided against it. It wasn’t very often that he was able to indulge in his secret fantasy and if this marked the start of being more open about it he wanted to savour the moment. Sitting down on the bed next to the pile of clothing Papyrus instead decided to put on the rest of the outfit first. Starting with the velour gloves.

Slipping them on didn’t take much effort, but Papyrus dragged it out. They came up pretty high on his arms and the snug fit didn’t escape him, Sans had remembered his bone size. Shivering slightly from the sensation of the fibers against his bones gave Papyrus an idea. He was already teasing himself, he may as well really enjoy it. Magic was already swirling around his bones in anticipation as he moved a gloved hand to stroke firmly against a floating rib. He almost cried out from how surprisingly good it felt, shuddering instead as he hissed through clenched teeth. He kept moving his gloved hand over the smooth bone, enjoying the sensations and the way it had him squirming Papyrus could feel his magic starting to form in his pelvis already from the light stimulation, but still he wanted to savour the moment as long as he could. 

Deciding on the thigh high socks next, Papyrus let his magic take the solid form. He always enjoyed this part, often forming his lower half outside of sexual situations because it allowed him to wear what he wanted. The long socks were something he really enjoyed wearing, and Sans enjoyed seeing him in. They were made of similar material to the gloves which made putting them on a little fiddly but it meant he could enjoy taking his time more. The socks looked great on him, his magic filling them out and he thought the detailing of having the individual toes was a nice touch. The feeling of the fabric against his formed flesh was different to rubbing on bone, but it was just as good. Papyrus caught himself caressing the tops of his thighs before he realised what he was doing. It didn’t take him long to realise that he was getting damp between his legs too. He wanted desperately to touch himself properly, but knew that leaving that until he was fully dressed would be more than worth the wait.

Papyrus wanted to leave the ears until last, so it was finally time to put on the pastel pink dress. He took the time to admire it properly now, unfolding it fully and turning it over in his hands. It was a simple design, but the material felt soft event through the gloves. Bringing it closer Papyrus let the material press softly against him as he studied the details as best he could in the low light. There was an adorable bow on the front of the outfit, and a small but very fluffy tale on the back. It was perfect, something straight out of his fantasies. Papyrus felt giddy with excitement; surely if Sans had gone through all this effort it meant he was somewhat interested too. Papyrus could wait no longer, he pulled the dress over himself with as much care as his shaking bones could manage.

If he had thought the gloves and socks were soft, they were nothing compared to the dress. Both inside and out the plush material felt amazing against his bare bone and flesh. Papyrus whimpered softly as he stood up from the bed, enjoying straightening the dress out a little too much. Out of the corner of his eye he spotted the flash of pink reflection in the mirror and he struggled to resist the temptation to sneak a peek at himself. Papyrus knew patience was a virtue he often lacked, but he really wanted to complete the outfit before he saw himself. Picking up the ears raised them up to his skull, adjusting them as much as he could from touch alone. He knew seeing himself was part of the appeal, but just the feeling of being in the full bunny outfit was quickening the beat of his soul. 

Papyrus stalled for a few more minutes, enjoying running his hands over his whole body. The sensations enough that he let out a few more whimpers, he wasn’t even trying to keep quiet now. Sans hadn’t given specific instructions for him to either stay in his room or come out to meet him, so Papyrus guessed his brother was either watching or listening. If Sans was being a pervert… he may as well give him a bit of a show and play along. Papyrus could wait no longer, he turned on his heels and headed over to the standing mirror. 

Strangely Papyrus hadn’t noticed that the corner of the room with the mirror had a new addition, he must have been too distracted beforehand. On the floor there was a small but powerful lamp, illuminating the area right before the mirror. Papyrus felt touched, Sans had really gone all out if he’d set something so sweet like this up. He giddily skipped over to the mirror, unable to contain his excitement any longer. _I Look REALLY Good_ Papyrus thought; he never was one to be overly modest. He wasn’t sure he thought that because the outfit suited him, or the fact he was really turned on wearing it. It didn’t matter, he was having a really good time checking himself out and adjusting the outfit. Such a good time in fact that he didn’t notice someone else was in the room until the main light was shut of.

”just where i want you”

Papyrus knew it unmistakably Sans who was in the room with him but in the darkness he felt the tingle of anticipation as he couldn’t quite figure out where his brother was. The smaller lamp acted like a sort of spotlight in the darkness, casting a hazy light over him and his reflection alone. Papyrus was beginning to think the lamp may have been a less than innocent purchase, Sans had planned it out just a little too well. Sans was being purposefully slow in making his way over, taking advantage of Papyrus being frozen to the spot. It wasn’t that he couldn’t move, but Papyrus suddenly felt very self conscious about sharing this fantasy with his brother. What if Sans didn’t like how he looked? Or thought it was really weird? Or-

“mmm- aren’t you just the cutest little fluffy bunny” Sans interrupted his thoughts by coming up behind him, grabbing Papyrus’s hips and lightly grinding against him. 

It seems Sans may have been more worked up than Papyrus anticipated if the erection digging into his ass was anything to go by.

“Sans- I-I- Nyeh-” Papyrus tried to speak but he was already so worked up, it felt like his mind had gone blank. 

“you look really great pap” Sans took hold of his hips and manoeuvred them both down to the floor “-but i wanna see more”

Sans used his vantage point to bring Papyrus back further until he was sat back and leaning against where he was kneeling. Their height difference meant that his lower position put them almost level, which Sans took advantage off by ghosting his breath against Papyrus’s skull seductivly. Both of them had their gaze glued to the mirror as Sans extended his hands to lightly pull Papyrus’s legs apart. Papyrus felt himself blush furiously at being in such a lewd position, but he found it hard to tear his eyes away from the mirror. He could see the soft shimmer of magical residue on his pussy illuminated by the lamp light. Part of him was embarrassed at being so turned on, but hearing his brother’s heavy breathing brushed away a lot of his fears. He knew whatever Sans had planned next he would really enjoy. 

“shit pap, you’re really enjoying this aren’t you?” Sans moved his hands back to wrap around Papyrus’s ribcage, pressing the soft material against his bones and making him whimper in response.

For a moment Papyrus thought Sans may just leave him high and dry and continue his teasing by not touching him.

He was wrong.

“how about you show me just how much you like it? go ahead and touch yourself little bunny-” Sans growled.

Usually his brother being so forward would fluster Papyrus more. But seeing himself in the mirror, lit up and exposed with only the faint outline of Sans being behind him made him shiver. With his legs spread this wide both of them could see every part of his magical flesh in the mirror. Papyrus would be lying if he said being on display like this wasn't a turn on. He felt the pressure of being watched while pleasuring himself, something he’d only had the nerve to do a handful of times in front of Sans. But something about being dressed up gave him confidence. He could pretend he wasn’t himself, but a hot bunny monster caught in throws of heat and begging for a mate. Papyrus whined with a voice full of need as he let a gloved hand drift to his core, drifting into the fantasy.

Watching himself closely in the mirror Papyrus started to run his covered fingers across his outer lips. He was giving himself the touch he had been craving yet he was still drawing the moment out, teasing both himself and the shadowy form of his brother behind him. He imagined that he was a young little bunny, in their first heat, captured by a much more dominant partner. Papyrus moaned as he circled the top of his pussy, thinking about being used and bred over and over by his mate. With how much he was worked up, the heat part wasn’t difficult to imagine at all. Papyrus could see Sans was getting just as worked up by his little display, in the dark of the room it was easier to pick out the whisp of Blue magic swirling in the darkness. It was something Papyrus would never tire seeing when his brother was really worked up. The soft glow of powerful blue magic was a lot more threatening in the darkness. Papyrus couldn’t help buck into his hand as he thought about Sans taking him roughly like a monster in heat. 

Watching himself in the mirror was fascinating in a way he hadn’t expected. He could see how flushed he’d become from playing with himself and could see his outfit becoming dishevelled. Some narcissistic part of his mind really enjoyed watching himself fall apart; seeing his eyes glaze over with lust and his pussy getting wetter. He’d never admit it, but he was getting really turned on watching himself, especially in his new outfit. Papyrus was getting more and more worked up, but he needed to do more than the teasing. He thought about putting his fingers inside right away but paused, he didn’t want to get the gloves dirty. They were already becoming damp with magic which made him feel a little bad, he hoped the weren’t ruined. Papyrus went to pull one of the gloves off before going any further, only to have Sans reach forward and still his hand. 

“don’t take them off, I know you have the that toy-” Sans paused to grab something out of his pockets and promptly handed the item to Papyrus “-but i thought you’d enjoy the real thing more”

Papyrus could not believe what Sans had handed to him. Even in the low light, the vibrant orange colour of the carrot in his hand was unmistakable. Papyrus would have felt embarrassed that Sans had found his vibrator shaped like the carrot in his hand, but he was already far too worked up. And now to have the opportunity of doing something with a real carrot? It felt so lewd, but that’s what made it more exciting. He used his free hand to spread himself open and positioned the tip of the carrot at his entrance, briefly feeling relief over how clean the carrot looked. Sans may have been lazy but, he knew he would take care over something like this. Anticipation buzzed around his bones as he slowly inserted the carrot, both him and his brother moaning at getting to see it reflected in the mirror. 

The phallic shape of the carrot meant it didn’t feel too different to his toy, but just the idea of having something in him that he shouldn’t made it feel amazing. Papyrus felt like he could feel every bump and ridge of the unique shape, constantly reminding him what it was. He started thrusting it in and out of himself in a steady pace, working himself up to take more and more each time. In the reflection he could see the carrot developing a wet orange sheen from his magic. Papyrus could feel and see how wet he was and it was driving him crazy in the best way. He used his free hand to roam all over his body, pressing the soft material of the glove against flesh and bone again. Moans were spilling out his mouth freely now and a couple of times he caught the reflection of his face when he did. This was something that would have put him off before, but now he was getting really into. It was naughty and lewd to watch himself and it was getting him really close. 

“just like that pap, fuck you look so hot right now-” Sans growled against him, pressing his hard length into Papyrus’s back almost in time with his thrusts “go faster little bunny, i wanna see you cum all over it”

Papyrus didn’t need to be told twice, he speed up the thrusting of the carrot and brought his spare hand to circle over the top of his mound. He could hear Sans grunting and his own moans as he watched his pussy start to twitch in his reflection. He’d never watched himself cum, he could feel the embarrassment from earlier leave him as he reached his peak and could see his body reacting. He tried to keep his blurry eyes focused on the way his pussy was sucking the carrot in further as he came, the movement of his other hand making his juices spill out around it. Even he had to admit, the sight of him exposed like this was really hot. He was beginning to understand why Sans liked watching him so much. 

Speaking of his brother, he could hear Sans’s breathing coming out between growls and grunts. Sans leaned over him slightly to start taking the carrot out as Papyrus had frozen a little in place as he rode out his climax. The carrot left him with an audible pop, making Sans growl more as he let his face move a little into the light. Papyrus was both a little horrified and even more turned on as he watched Sans bring the used carrot to his mouth. In the low light Sans’s Blue tongue lit up his features from below almost sinisterly as he licked across the carrot. Sans wasn’t letting any of his cum go to waste, wrapping his tongue in such a way it sent a jolt of pleasure through Papyrus’s body just from watching. Sans knew he had his focus, Papyrus could feel him chuckle as he put the tip of the carrot in his mouth fully, biting down on the end. Sans groaned while making eye contact, enjoying watching his brother squirm against him. It didn’t seem like Sans was going to give him a real chance to recover, he finished his mouthful before discarding the carrot and pulling his own shorts down. 

“so sweet, tastes so much better with you on it,we should do this more often...but for now-” Sans Hooked his hands under Papyrus’s thighs, bringing him flush against his chest while still spreading him wide. He lifted Papyrus until he was balancing on the balls of his feet, his entrance positioned just over Sans’s hard cock “-i’ve heard rabbits like to fuck like this-”

Sans sank into him before Papyrus had time to process what his brother was implying. He didn't have to wonder for long, the pace Sans set up was so hard and fast Papyrus wouldn't be surprised if he ended up bruised. In this position he was spread open wide, his feet barely touching the floor as sans supported most of his weight. Not able to find a counterbalance on the floor Papyrus flung his arms back over his head and clutched at any part of Sans he could reach. There was no use trying to be quiet. Sans was thrusting hard and deep and his hands were gripping the formed flesh of his thighs hard enough to leave marks. 

“hng- that’s it pap scream for me, you love being fucked this hard don’t you?” Sans moaned, his grip became tighter as his cock reached deep enough for Papyrus to see stars.

Watching himself in the mirror was the only thing Papyrus could focus on, it felt _So Good_. He tried to respond right away, but it just came out as moans as Sans hit his spot on almost every thrust. Papyrus could see where they were joined in the reflection, the mixture of blue and orange brighter in the dark. He could even see his magic shaded where Sans was moving inside him. His ears were almost falling off and his costume was wet in places from sweat and cum, but he didn’t care. He looked absolutely destroyed, and the sight was making him approach his second orgasm fast. 

“ I-I’m So Close Again Nye-Please!”

“close already? you just loved getting fucked like animal by your big bros cock huh? ah fuck papy” Sans moaned loud, clearly reaching his own peak to as he slammed his hips up hard “- i’m gonna fill you up you dirty little bunny- wanna hear you scream my name when you cum”

Papyrus was almost crying from the intensity being pounded so hard, but he loved it. He was so close he could taste it, and he knew Sans wasn't far behind. He focused on how hard his brother's cock felt inside him as he watched himself clamping down in their reflection. It was the softness of the dress grazing over his ribs on every thrust, contrasting with the almost painful pace that finally made him let go and loose himself to the sensations. 

“Sans! I- I’m Cumming Fuc-” Papyrus cried out, no longer caring about his use of language.

He was a dirty little bunny, and he loved it. 

Sans growled before biting down on his clavicle and releasing inside him. Being filled up just prolonged his pleasure and the sharp pain from the bite had him shaking. Sans Stayed buried in him for a few more moments before lowering him down gently, collapsing into a sitting position himself. Papyrus felt tingly all over as he came down from his high, but he had the passing notion to compliment Sans on the effort and energy he put into their lovemaking. But that could come later, for now he whimpered happily as Sans pulled him back into an embrace as they panted together on the floor. 

“holy shit pap that was so good… are you ok?” Sans asked eventually, placing a kiss lazily against his skull. 

“Are You Sure You Don't Think I’m Weird?” Papyrus murmured groggily.

“no way bro, i loved it. I had more planned but you just looked so hot…” Sans trailed off a little, planting a few more kisses on his skull affectionately “-we’ll just have to save the egg toys for next time”

“eggs? What can you do with eggs?” Papyrus asked.  
Sans chuckled low in response, sending shivers up Papyrus’s spine. He knew that laugh, it was reserved for whenever his brother had a particularly perverted plan. 

“oh pap you have no idea”

**Author's Note:**

> i know i'm trash, it's in my name  
> come yell at me on tumblr about it too if you want @MeGaLoTrash


End file.
